> Also, and correct me if I'm wrong but drifting further into the Masters of Kin realm
> and Olde Double Standard Towne, there is also an invisible line that was made around
> 1997 that serves as a cutoff for hacks. While I'm not advocating adding all hacks
> after 1997, you must admit it's borderline madness that anything before that line
> gets added without question and everything after is a mess.
I'm not aware of any such invisible line..
There are a whole bunch of Korean hacks made after that date which are supported, there are NeoGeo bootlegs newer than that etc. There are PGM games that were found on carts too. If 1997 is anything it's the point at which there really aren't a significant amount of games from any of the major manufacturers that MAME can emulate well as most had switched to more complex platforms.
Also previously a bunch of hacks from the 80s were removed, and only reinstated in the last few years because they still kept showing up on PCBs so it was realised that removing them was a mistake.
As I said, things just get looked at on a case-by-case basis.
It's important to document things which are part of the arcade scene, be it current or past, because 20 years from now MAME needs to show what happened, and the things that are happening now are still part of that.
People doing things specifically to try and get them into MAME will likely just be ignored, things that actually seem to be of worth will be looked at.
The hacks found on PCBs that usually don't get added are just cases where an arcade operator has hacked a date, there's nothing creative, memorable, or worthwhile about that at all. Cases with significant code modifications are more interesting, cases where games shipped under different names and it's those names people remember likewise.
Some hacks have real historical value, because they were a starting point for a developer who then moved on to other things (it's been said before that Toaplan's(?) early Mahjong stuff was just hacks for example) There are also odd cases where what look to be simply hacks were presented as official games "Super Moon Cresta" being an example, it's clearly just a hack but that hack is apparently the Grelmin 'Original' Likewise pretty much all the Taito Brasil stuff is unofficially hacked / translated / modified to run on other hardware, clearly without approval of Taito Japan.
Then we've got weird ones, like what look like 100% legitimate alt sets from companies really only known to bootleg games. One of the Spanish Puckman sets actually looks like a different code revision specifically made for the usual Spanish coinage setup, all the code is offset, so unless somebody very carefully went over every line of the code and adjusted all the offsets / jumps then it's probably somehow an original set they got Namco to make (and really if you just wanted to hack in the coinage stuff there are far easier ways to do it) We could have just dismissed everything that company put out as a hack, because most of their products are, then we would have missed that one.
Bootlegs can tell interesting stories about which protections bootleggers had manage to crack, which they hadn't, what type of hardware was cost effective to clone, what wasn't etc. (especially with sound systems, where you see most bootleggers opted for the cheapest they could go) In some cases the bootlegs we have look like a labour of love, an awful lot of work gone into replacing the protection routines, even rewriting parts of the game to work with different hardware or where code has been painstakingly reconstructed from split encrypted/decrypted code and data, it's an absolutely fascinating subject at code level.